In some circumstances, an existing wellbore may become unusable, for example, due to structural issues (such as, casing collapse or parting, etc.) or fluid/pressure issues (such as, a blowout or poor cement integrity, etc.). However, a section of the wellbore may be salvageable for further production or injection use. Therefore, it will be appreciated that improvements are continually needed in the arts of constructing well systems and providing contingency measures in such circumstances. These improvements may be useful whether or not any section or all of an existing wellbore is considered usable.